Finite Larmor radius effects on E x B weak turbulence transport

Kryukov, N.; Martinell, Julio J.; del-Castillo-Negrete, Diego B.

doi:10.1017/S0022377818000351

Title: Finite Larmor radius effects on E x B weak turbulence transport

Journal Article · Tue May 01 00:00:00 EDT 2018 · Journal of Plasma Physics

DOI:https://doi.org/10.1017/S0022377818000351· OSTI ID:1515689

Kryukov, N. ^[1]; Martinell, Julio J. ^[1];

^[2]

Univ. Nacional Autonoma de Mexico (Mexico)
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

Transport of test particles in two-dimensional weak turbulence with waves propagating along the poloidal direction is studied using a reduced model. Finite Larmor radius (FLR) effects are included by gyroaveraging over one particle orbit. For low wave amplitudes the motion is mostly regular with particles trapped in the potential wells. As the amplitude increases the trajectories become chaotic and the Larmor radius modifies the orbits. For a thermal distribution of Finite Larmor radii the particle distribution function (PDF) is Gaussian for small $$\unicode[STIX]{x1D70C}_{th}$$ (thermal gyroradius) but becomes non-Gaussian for large $$\unicode[STIX]{x1D70C}_{th}$$. Furthermore, the time scaling of transport is diffusive, as characterized by a linear dependence of the variance of the PDF with time. An explanation for this behaviour is presented that provides an expression for an effective diffusion coefficient and reproduces the numerical results for large wave amplitudes which implies generalized chaos. When a shear flow is added in the direction of wave propagation, a modified model is obtained that produces free-streaming particle trajectories in addition to trapped ones; these contribute to ballistic transport for low wave amplitude but produce super-ballistic transport in the chaotic regime. As in the previous case, the PDF is Gaussian for low $$\unicode[STIX]{x1D70C}_{th}$$ becoming non-Gaussian as it increases. The perpendicular transport presents the same behaviour as in the case with no flow but the diffusion is faster in the presence of the flow.

View Accepted Manuscript (DOE)

Cite

Export

Save

Research Organization:: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)

Sponsoring Organization:: USDOE Office of Science (SC)

Grant/Contract Number:: AC05-00OR22725

OSTI ID:: 1515689

Journal Information:: Journal of Plasma Physics, Vol. 84, Issue 3; ISSN 0022-3778

Publisher:: Cambridge University PressCopyright Statement

Country of Publication:: United States

Language:: English

Citation Metrics:

Cited by: 3 works

Citation information provided by
Web of Science

References (16)

Finite Larmor radius effects on test particle transport in drift wave-zonal flow turbulence Dewhurst, J. M.; Hnat, B.; Dendy, R. O. Plasma Physics and Controlled Fusion, Vol. 52, Issue 2 https://doi.org/10.1088/0741-3335/52/2/025004	journal	January 2010
Stochastic ion heating by a lower hybrid wave: II Karney, Charles F. F. Physics of Fluids, Vol. 22, Issue 11 https://doi.org/10.1063/1.862512	journal	January 1979
Stochastic E×B particle transport Kleva, Robert G.; Drake, J. F. Physics of Fluids, Vol. 27, Issue 7 https://doi.org/10.1063/1.864823	journal	January 1984
Mechanisms and dynamics of the external transport barrier formation in non-linear plasma edge simulations Chôné, L.; Beyer, P.; Sarazin, Y. Nuclear Fusion, Vol. 55, Issue 7 https://doi.org/10.1088/0029-5515/55/7/073010	journal	June 2015
Gyrokinetic particle simulation model Lee, W. W. Journal of Computational Physics, Vol. 72, Issue 1 https://doi.org/10.1016/0021-9991(87)90080-5	journal	September 1987
Gyrokinetic simulations of turbulent transport Garbet, X.; Idomura, Y.; Villard, L. Nuclear Fusion, Vol. 50, Issue 4 https://doi.org/10.1088/0029-5515/50/4/043002	journal	March 2010
Gyroaverage effects on chaotic transport by drift waves in zonal flows Martinell, Julio J.; del-Castillo-Negrete, Diego Physics of Plasmas, Vol. 20, Issue 2 https://doi.org/10.1063/1.4790639	journal	February 2013
Drift wave test particle transport in reversed shear profile Horton, Wendell; Park, Hyoung-Bin; Kwon, Jae-Min Physics of Plasmas, Vol. 5, Issue 11 https://doi.org/10.1063/1.873110	journal	November 1998
Chaotic transport by Rossby waves in shear flow del‐Castillo‐Negrete, Diego; Morrison, P. J. Physics of Fluids A: Fluid Dynamics, Vol. 5, Issue 4 https://doi.org/10.1063/1.858639	journal	April 1993
Area-preserving maps models of gyroaveraged E×B chaotic transport da Fonseca, J. D.; del-Castillo-Negrete, D.; Caldas, I. L. Physics of Plasmas, Vol. 21, Issue 9 https://doi.org/10.1063/1.4896344	journal	September 2014
Regular and Chaotic Dynamics Lichtenberg, A. J.; Lieberman, M. A. Applied Mathematical Sciences https://doi.org/10.1007/978-1-4757-2184-3	book	January 1992
Transport properties of energetic particles in a turbulent electrostatic field Manfredi, G.; Dendy, R. O. Physics of Plasmas, Vol. 4, Issue 3 https://doi.org/10.1063/1.872159	journal	March 1997
Chaotic transport in zonal flows in analogous geophysical and plasma systems del-Castillo-Negrete, Diego Physics of Plasmas, Vol. 7, Issue 5 https://doi.org/10.1063/1.873988	journal	May 2000
A statistical study of gyro-averaging effects in a reduced model of drift-wave transport da Fonseca, J. D.; del-Castillo-Negrete, D.; Sokolov, I. M. Physics of Plasmas, Vol. 23, Issue 8 https://doi.org/10.1063/1.4961430	journal	August 2016
Asymmetric transport and non-Gaussian statistics of passive scalars in vortices in shear del-Castillo-Negrete, D. Physics of Fluids, Vol. 10, Issue 3 https://doi.org/10.1063/1.869585	journal	March 1998
Finite Larmor radius effects on nondiffusive tracer transport in a zonal flow Gustafson, K.; del-Castillo-Negrete, D.; Dorland, W. Physics of Plasmas, Vol. 15, Issue 10 https://doi.org/10.1063/1.3003072	journal	October 2008